From de10ce58e295c7f4419976384be92d2b7407056f Mon Sep 17 00:00:00 2001
From: Pascal Zittlau <pascal.zittlau@gmail.com>
Date: Wed, 17 Dec 2025 10:14:05 +0100
Subject: [PATCH] fix flaky tests

---
 docs/TODO.md    |  2 +-
 src/Patcher.zig |  2 +-
 src/main.zig    | 57 ++++++++++++++++++++++---------------------------
 3 files changed, 28 insertions(+), 33 deletions(-)

diff --git a/docs/TODO.md b/docs/TODO.md
index e2888d9..0468f93 100644
--- a/docs/TODO.md
+++ b/docs/TODO.md
@@ -22,7 +22,7 @@ IvyBridge(2012) and AMD Zen 2 Family 17H(2019) and Linux 5.9(2020).
 - [ ] JIT support: intercept `mmap`, `mprotect` and `mremap` that change pages to be executable
 - [ ] `SIGILL` patching fallback
 - [x] `vdso` handling
-- [ ] check why the libc tests are flaky
+- [x] check why the libc tests are flaky
 
 ## Minor things
 
diff --git a/src/Patcher.zig b/src/Patcher.zig
index 344f46f..f40f6e7 100644
--- a/src/Patcher.zig
+++ b/src/Patcher.zig
@@ -854,7 +854,7 @@ fn ensureRangeWritable(
         const gop = try allocated_pages.getOrPut(gpa, page_addr);
         if (gop.found_existing) {
             const ptr: [*]align(page_size) u8 = @ptrFromInt(page_addr);
-            try posix.mprotect(ptr[0..page_addr], protection);
+            try posix.mprotect(ptr[0..page_size], protection);
         } else {
             const addr = posix.mmap(
                 @ptrFromInt(page_addr),
diff --git a/src/main.zig b/src/main.zig
index a0e8bd8..573e9e5 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -332,10 +332,9 @@ test "nolibc_nopie_exit" {
 test "nolibc_pie_exit" {
     try testHelper(&.{ flicker_path, getTestExePath("nolibc_pie_exit") }, "");
 }
-// BUG: This one is flaky
-// test "libc_pie_exit" {
-//     try testHelper(&.{ flicker_path, getTestExePath("libc_pie_exit") }, "");
-// }
+test "libc_pie_exit" {
+    try testHelper(&.{ flicker_path, getTestExePath("libc_pie_exit") }, "");
+}
 
 test "nolibc_nopie_helloWorld" {
     try testHelper(&.{ flicker_path, getTestExePath("nolibc_nopie_helloWorld") }, "Hello World!\n");
@@ -343,10 +342,9 @@ test "nolibc_nopie_helloWorld" {
 test "nolibc_pie_helloWorld" {
     try testHelper(&.{ flicker_path, getTestExePath("nolibc_pie_helloWorld") }, "Hello World!\n");
 }
-// BUG: This one is flaky
-// test "libc_pie_helloWorld" {
-//     try testHelper(&.{ flicker_path, getTestExePath("libc_pie_helloWorld") }, "Hello World!\n");
-// }
+test "libc_pie_helloWorld" {
+    try testHelper(&.{ flicker_path, getTestExePath("libc_pie_helloWorld") }, "Hello World!\n");
+}
 
 test "nolibc_nopie_printArgs" {
     try testPrintArgs("nolibc_nopie_printArgs");
@@ -354,10 +352,9 @@ test "nolibc_nopie_printArgs" {
 test "nolibc_pie_printArgs" {
     try testPrintArgs("nolibc_pie_printArgs");
 }
-// BUG: This one is flaky
-// test "libc_pie_printArgs" {
-//     try testPrintArgs("libc_pie_printArgs");
-// }
+test "libc_pie_printArgs" {
+    try testPrintArgs("libc_pie_printArgs");
+}
 
 test "nolibc_nopie_readlink" {
     try testReadlink("nolibc_nopie_readlink");
@@ -365,7 +362,7 @@ test "nolibc_nopie_readlink" {
 test "nolibc_pie_readlink" {
     try testReadlink("nolibc_pie_readlink");
 }
-// BUG: This one just outputs the path to the flicker executable and is likely also flaky
+// BUG: This one just outputs the path to the flicker executable
 // test "libc_pie_readlink" {
 //     try testReadlink("libc_pie_readlink");
 // }
@@ -396,10 +393,6 @@ test "nolibc_pie_clone_no_new_stack" {
     );
 }
 
-test "echo" {
-    try testHelper(&.{ "echo", "Hello", "There" }, "Hello There\n");
-}
-
 test "nolibc_nopie_fork" {
     try testHelper(
         &.{ flicker_path, getTestExePath("nolibc_nopie_fork") },
@@ -412,13 +405,12 @@ test "nolibc_pie_fork" {
         "Child: I'm alive!\nParent: Child died.\n",
     );
 }
-// BUG: This one is flaky
-// test "libc_pie_fork" {
-//     try testHelper(
-//         &.{ flicker_path, getTestExePath("libc_pie_fork") },
-//         "Child: I'm alive!\nParent: Child died.\n",
-//     );
-// }
+test "libc_pie_fork" {
+    try testHelper(
+        &.{ flicker_path, getTestExePath("libc_pie_fork") },
+        "Child: I'm alive!\nParent: Child died.\n",
+    );
+}
 
 test "nolibc_nopie_signal_handler" {
     try testHelper(
@@ -445,13 +437,16 @@ test "nolibc_pie_vdso_clock" {
         "Time gotten\n",
     );
 }
-// BUG: This one is flaky
-// test "libc_pie_vdso_clock" {
-//     try testHelper(
-//         &.{ flicker_path, getTestExePath("libc_pie_vdso_clock") },
-//         "Time gotten\n",
-//     );
-// }
+test "libc_pie_vdso_clock" {
+    try testHelper(
+        &.{ flicker_path, getTestExePath("libc_pie_vdso_clock") },
+        "Time gotten\n",
+    );
+}
+
+test "echo" {
+    try testHelper(&.{ "echo", "Hello", "There" }, "Hello There\n");
+}
 
 fn testPrintArgs(comptime name: []const u8) !void {
     const exe_path = getTestExePath(name);